Cyclophosphamide-immunodepressed FVB/N mice: potentiating the effects of testicular cytomegalovirus infection

The aim of this study was to investigate the effect of cyclophosphamide (CY) immunosuppression on the infection of germinal cells following testicular inoculation of male FVB/N mice with murine cytomegalovirus (MCMV). We used CY to modulate the immune status in order to mimic iatrogenic immunosuppression in humans (organ transplantation) as closely as possible. We show that viral pathological manifestations observed in mice treated with this CY-MCMV combination were severer than those observed in immunocompetent male mice infected with MCMV alone. As previously reported, the typical MCMV cellular inclusions were present in interstitial spaces; however, the spermatogenic cells were never directly infected. Nonetheless, at the end of our observation, we obtained definitive necrosis of the testes. These results suggest that germline cell necrosis induces sterility in immunodepressed infected male mice indirectly. In the case of organ transplantation, particular attention should be accorded to male patients receiving CY.

Failure to infect embryos after virus injection in mouse zygotes

BACKGROUND

The intracytoplasmic injection of sperm raises the problem that viral elements may be transported into the oocyte by the spermatozoon or the surrounding medium. It also raises questions about how the developing zygote will behave.

METHODS

We used the murine model to microinject murine cytomegalovirus (MCMV) into the zygote ooplasm and followed the changes in these microinjected zygotes in vivo and in vitro over time.

RESULTS

80% of zygotes microinjected with viral suspension, and 80% injected with medium alone, survived. Although MCMV DNA was detected in 56% of injected embryos, up until the blastocyst stage, the mice born from these injected zygotes developed normally and did not contain MCMV DNA. When embryonic stem cells were co-incubated with MCMV and then transferred into healthy blastocysts, the offspring were normal and did not contain any MCMV DNA.

CONCLUSIONS

Our observations suggest that even if MCMV DNA persists from the zygote to the blastocyst stage, its presence has no detrimental effect on pre-implantation or post-implantation development.

Experimental inoculation of male mice with murine cytomegalovirus and effect on offspring

BACKGROUND

Murine cytomegalovirus (MCMV) was used to examine aspects of viral infection in male mice, and its possible transmission to their offspring.

METHODS AND RESULTS

FVB/N mice inoculated intratesticularly with 5x10(5) plaque forming units (PFU) of MCMV, developed peritoneal haemorrhagic exudates, spleen hypertrophy and acute local infection. Infectiousness was detected until 15 days post-inoculation (D15 PI) in the genital organs, and virus DNA up to D35 PI. Testicular endothelial and Leydig cells were infected, and peritubular cells severely damaged. Spermatogenesis was affected, but neither germ cells nor Sertoli cells were infected. No virus was found in the epididymal epithelial cells. Viral DNA was detected in cells extracted from vas deferens samples until D15 PI. Neither infectious virus nor viral DNA were found in spermatozoa recovered from uterine fluid, fertilized oocytes, blastocysts, fetal tissues or newborn animals following the mating of infected males with uninfected females.

CONCLUSIONS

MCMV harboured in the male genital organs was not transmitted to their offspring, even when mating occurred during the acute phase of CMV disease. Although the infection may have had an impact on spermatogenesis, fertility was not affected. These results do not support the hypothesis of conceptus MCMV infection by the fertilizing spermatozoon in natural conception.

Novel molecular variants of the Na-K-2Cl cotransporter gene are responsible for antenatal Bartter syndrome

Antenatal Bartter syndrome is a variant of inherited renal-tubular disorders associated with hypokalemic alkalosis. This disorder typically presents as a life-threatening condition beginning in utero, with marked fetal polyuria that leads to polyhydramnios and premature delivery. Another hallmark of this variant is a marked hypercalciuria and, as a secondary consequence, the development of nephrocalcinosis and osteopenia. We have analyzed 15 probands belonging to 13 families and have performed SSCP analysis of the coding sequence and the exon-intron boundaries of the NKCC2 gene; and we report 14 novel mutations in patients with antenatal Bartter syndrome, as well as the identification of three isoforms of human NKCC2 that arise from alternative splicing.